Scientific disciplines, as we know them, are a fairly recent invention. As late as the 18th century, both amateur and professional scientists let their intellect range unfettered. The great Renaissance painter Leonardo da Vinci explored architecture, engineering, geology, botany and more. He is credited with inventing the helicopter, a diving suit and painting the Mona Lisa.

Only later did scientific disciplines emerge as a powerful way to speed learning as scientific knowledge accumulated rapidly. Today's scientists, including this year’s SN 10 researchers, are stepping over these boundaries to borrow tools and inspiration from other fields to solve knotty questions facing science and society.

Members of the SN 10 class of 2018 are skilled at moving between scientific worlds. One uses physics to learn how cell movement in the lungs encourages asthma. Another sees architecture in how volcanoes build planets. Several venture into other fields to help answer difficult questions in their own fields: Maybe the proteins of biology can teach a materials scientist how to make self-repairing batteries.

This is the fourth year that Science News is spotlighting a group of early- and mid-career scientists who are breaking ground. It’s a confident, tough group. Try to set limits or box these people in and they bristle. Some had childhood experiences that opened their minds to the possibilities of scientific research. Others dug in their heels to do something that an adult said would be too difficult.

From a pool of standout researchers nominated by Nobel laureates and recently elected members of the National Academy of Sciences, Science News staff chose 10 to introduce on these pages. The scientists, all under 40, come from different backgrounds and fields of study. But their colleagues and mentors describe many of them in the same way: fearless, with a thirst for knowledge and a drive to grasp the unknown, boundaries be damned. — Cori Vanchieri